Late Onset Neonatal Sepsis Due to Hafnia alvei in Three Neonates at the University of Nigeria Teaching Hospital, Enugu, Nigeria

Background: Hafnia alvei is a Gram-negative motile bacillus, belonging to the Enterobacteriaceae family. It is commonly found in stool of humans and animals and soil. It is very rare in neonates. This organism is resistant to most commonly used antibiotics, and causes nosocomial outbreaks with significant mortality. Therefore, awareness regarding this organism is important to improve outcome.

Presentation of Cases: We report three cases of late onset neonatal sepsis caused by Hafnia alvei. Of these, two were preterm while one was term. The term neonate was referred on account of perinatal asphyxia and developed fever, reduced activity, tachycardia, and tachypnoea 5 days into admission. The two preterm neonates were delivered at the index hospital and developed hypothermia, and other symptoms on the 4th day of life. Two sets of blood cultures were done for each case after collecting blood from two different sites. Blood culture was done using BACT/ALERT 3D (BioMerieux, Marcy I’Etoile, France) which uses a colorimetric sensor and reflects light to monitor the presence of carbon dioxide produced by micro-organisms. This yielded Hafnia alvei in all three samples after 72 hours of incubation. Gram stain done showed presence of Gram negative bacilli and subculture was done on MacConkey and 5% sheep agar incubated at 37 0 C for 18-24 hours. Identification of isolates was done with standard biochemical test and confirmed with API 20 E identification system (BioMerieux, Marcy I’Etoile, France). Antibiotic sensitivity was done using the modified Kirby Bauer disc diffusion method (Oxoid, Cambridge, UK). At most five antibiotic discs were used for each isolate and these were incubated at 370C for 24 hours. Isolates were sensitive to fluoroquinolones, cefepime and meropenem. Patients received intravenous antibiotics for two weeks, phototherapy and exchange blood transfusion. They were subsequently discharged and are currently on follow up.

Discussion and Conclusion: Though rare, three infections with H. alvei were reported in this study. The isolates were sensitive to fluoroquinolones, cefepime and meropenem and resistant to amoxicillin/clavulanic acid, piperacillin/tazobactam. The outcomes were improved by a high index of suspicion, early diagnosis, prompt institution of appropriate antibiotics and supportive care.